1. Field of the Invention
The present invention relates to a connecting element inspecting method and a connecting element inspecting device for detecting a state where terminals are mounted in terminal containing holes, inclusion of foreign materials into the terminal containing holes, and the like in a connecting element such as a connector or a socket and judging whether the connecting element is accepted or rejected.
2. Description of the Related Art
In a connecting element, for example, a connector, a terminal has been conventionally inserted into a terminal containing hole opening to a connecting surface to another connector to a predetermined position from the rear thereof. In the connector, the terminal is generally held in the predetermined position by a lance provided on the side of a connector housing or on the side of the terminal.
A lot of connectors fabricated include one in which a terminal is not inserted to the above described predetermined position. Such a connector must be eliminated by inspection.
Therefore, examples of a conventionally known inspecting device for inspecting a connector include one so adapted as to elastically push a front end of a terminal by a pin elastically urged by a spring and mechanically push out the terminal incompletely inserted and then, check the conduction of the terminal (see Japanese Utility type Laid-Open Gazette No. 47093/1987).
There exists a connector in a so-called half-inserted state in which a terminal is not completely inserted to a predetermined position, although it is engaged with a connector housing in such a extent that it receives an engaging force at a certain level by a lance. When such a connector in a half-inserted state is inspected by the above described inspecting device, the terminal can be generally pushed out by an urging force produced by a pin. If each electric wire is bound by tape winding or the like, however, the terminal cannot be pushed out by the urging force produced by the pin, so that the connector passes the check of the conduction. When this connector is actually connected to another connector, the terminal is pushed out by a corresponding terminal in the other connector or the terminal is moved by causes such as vibration during its use, so that the connector is incompletely connected.
In the above described inspecting device, therefore, it is considered that the urging force of the spring for urging the pin is increased. In this case, however, the terminal is deformed, plating on the surface of the terminal is stripped and therefore, the connector housing is damaged.
With the progress of electronic control in automobiles, a connector used for a wiring harness in each of the automobiles has been made multipolar and miniaturized in recent years. When an attempt to inspect such a small-sized and multipolar connector is made using the above described inspecting device, the above described pin cannot be inserted into a terminal containing hole because the terminal containing hole is very narrow. In addition, even if the pin can be inserted, a too large pressing force cannot be exerted on a small-sized terminal which is easily deformed, thereby to make it impossible to detect a half-inserted state.
On the other hand, it is also considered that a state where a terminal is mounted is judged by visual verification of human beings. In this case, however, the inspection efficiency is significantly low, and the inspection precision varies. Further, it cannot be possible to detect a half-inserted state of the terminal (a state where the position of the terminal is shifted by approximately 0.2 to 0.3 mm from its correct inserted state).